1. Field of the Invention
The present invention relates to a technique for compressing and editing image data files.
2. Description of the Related Art
One of known techniques for separating multi-valued document image data into image areas and compressing the image areas is to separate a document image into a character portion and a figure portion and compress the character portion and the figure portion using the modified read (MMR) and Joint Photographic Experts Group (JPEG) formats, respectively.
However, it is difficult to reconstruct image files, once created, using image objects having different compression formats. Thus, for example, if a plurality of image files are combined to create a single image file, there is a problem in that the file size of a multipage image file created by combining files becomes too large depending on the number of files combined or the file size of each file.
Further, in general, in a situation where multipage image files such as Portable Document Format (PDF) files, lossy compressed files such as JPEG files, and uncompressed files such as Tagged Image File Format (TIFF) files exist, each image file or page is separated into a character region and a background region. In this case, it is not possible to reconstruct image files using image objects having different compression formats and combine the files to create a multipage image file.
Further, as known in the art, a method of displaying, in a thumbnail image, information indicating whether or not an image file has text data added thereto to allow a user to easily recognize attribute is implemented as software. However, information indicating whether or not a character region and a background region, which are separated from each other, are composed of image objects having different compression formats is not displayed. Thus, a problem occurs in that a user is not able to easily recognize the compression state of images.